It is customary to use a thermocouple to measure temperature in high pressure, high temperature environments as those associated with autoclaves, furnaces, boilers, etc. However, known thermocouples are of the typical duplex wire construction which permits vacuum and/or steam leakage between and along the insulated conductors. These conductors are wrapped with a sleeve of insulation around which a jacket is positioned to contain each insulated wire. Unfortunately, air spaces are formed between each sleeve of insulation and the jacket which permit the aforementioned vacuum and/or steam leakage to occur. The air space reduces the efficiency of the vacuum unit.
Other thermocouples utilize an epoxy to fill any air spaces that may exist between the insulated conductors and the jacket. With this configuration, the epoxy or sealing substance can be drawn into the vacuum within the autoclave during operation.
Additionally, the traditional duplex wire used in the known thermocouples is sized and shaped so that a good seal is jeopardized where the thermocouple passes through the autoclave door.
Moreover, it has been normal practice for the industrial user to purchase wire and produce the thermocouple in-house, afterwhich the thermocouple is reused several times. Unfortunately, if accurate readings of temperature are necessary, the reworked thermocouple must be recalibrated, rechecked for any damage or malfunctioning problems and one end reformed for entry into the autoclave. The procedure of refitting the known thermocouple for reuse requires extra equipment and manhours which translates into reduced cost-effectiveness.